Ultraviolet photography and spectroscopy using a spectrally selective image converter

Ultraviolet spectroscopy and photography using spectrally selective image converte

Manual for 70 mm hand-held photography from Skylab

A manual and atlas used on the Skylab mission for hand-held photography are presented. The manual covers terrain, environmental, meteorological, and dim light photography while the atlas covers sections from the Army Map Service 1:40.000,000 world map, a glossary of geologic terms, geologic maps, and recommended exposure times

CHARACTERISTICS OF THE INCREASED ADRENOCORTICAL FUNCTION OBSERVED IN MANY OBESE PATIENTS *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75360/1/j.1749-6632.1965.tb34805.x.pd

Managing Individual Workplace Grievances and Disciplinary Procedures

This paper examines ways of effectively managing individual workplace grievances and disciplinary procedures. There are three principle areas that will be the focus of this page: • dealing with conflict between co-workers; • managing workplace complaints and investigation procedures; and • implementing appropriate disciplinary procedures. These issues on the whole tend to be aired in the course of unfair dismissal proceedings, when the substantive and procedural fairness of a dismissal is considered. However, good HR practices should ensure that the issues are well managed from the outset through established procedures, long before the issue of unfair dismissal arises

The Retracing Boomerang Attack

Boomerang attacks are extensions of differential attacks, that make it possible to combine two unrelated differential properties of the first and second part of a cryptosystem with probabilities $p$ and $q$ into a new differential-like property of the whole cryptosystem with probability $p^2q^2$ (since each one of the properties has to be satisfied twice). In this paper we describe a new version of boomerang attacks which uses the counterintuitive idea of throwing out most of the data (including potentially good cases) in order to force equalities between certain values on the ciphertext side. This creates a correlation between the four probabilistic events, which increases the probability of the combined property to $p^2q$ and increases the signal to noise ratio of the resultant distinguisher. We call this variant a retracing boomerang attack since we make sure that the boomerang we throw follows the same path on its forward and backward directions. To demonstrate the power of the new technique, we apply it to the case of 5-round AES. This version of AES was repeatedly attacked by a large variety of techniques, but for twenty years its complexity had remained stuck at $2^{32}$. At Crypto\u2718 it was finally reduced to $2^{24}$ (for full key recovery), and with our new technique we can further reduce the complexity of full key recovery to the surprisingly low value of $2^{16.5}$ (i.e., only 90,000 encryption/decryption operations are required for a full key recovery on half the rounds of AES). In addition to improving previous attacks, our new technique unveils a hidden relationship between boomerang attacks and two other cryptanalytic techniques, the yoyo game and the recently introduced mixture differentials

New Slide Attacks on Almost Self-Similar Ciphers

The slide attack is a powerful cryptanalytic tool which has the unusual property that it can break iterated block ciphers with a complexity that does not depend on their number of rounds. However, it requires complete self similarity in the sense that all the rounds must be identical. While this can be the case in Feistel structures, this rarely happens in SP networks since the last round must end with an additional post-whitening subkey. In addition, in many SP networks the final round has additional asymmetries -- for example, in AES the last round omits the MixColumns operation. Such asymmetry in the last round can make it difficult to utilize most of the advanced tools which were developed for slide attacks, such as deriving from one slid pair additional slid pairs by repeatedly re-encrypting their ciphertexts. In this paper we overcome this last round problem by developing four new types of slide attacks. We demonstrate their power by applying them to many types of AES-like structures (with and without linear mixing in the last round, with known or secret S-boxes, with 1,2 and 3 periodicity in their subkeys, etc). In most of these cases, the time complexity of our attack is close to $2^{n/2}$, which is the smallest possible complexity for slide attacks. Our new slide attacks have several unique properties: The first attack uses slid sets in which each plaintext from the first set forms a slid pair with some plaintext from the second set, but without knowing the exact correspondence. The second attack makes it possible to create from several slid pairs an exponential number of new slid pairs which form a hypercube spanned by the given pairs. The third attack has the unusual property that it is always successful, and the fourth attack can use known messages instead of chosen messages, with only slightly higher time complexity

Mixture Integral Attacks on Reduced-Round AES with a Known/Secret S-Box

In this work, we present new low-data secret-key distinguishers and key-recovery attacks on reduced-round AES. The starting point of our work is “Mixture Differential Cryptanalysis” recently introduced at FSE/ToSC 2019, a way to turn the “multiple-of-8” 5-round AES secret-key distinguisher presented at Eurocrypt 2017 into a simpler and more convenient one (though, on a smaller number of rounds). By reconsidering this result on a smaller number of rounds, we present as our main contribution a new secret-key distinguisher on 3-round AES with the smallest data complexity in the literature (that does not require adaptive chosen plaintexts/ciphertexts), i.e. approximately half of the data necessary to set up a 3-round truncated differential distinguisher (which is currently the distinguisher in the literature with the lowest data complexity). E.g. for a probability of success of 95%, our distinguisher requires just 10 chosen plaintexts versus 20 chosen plaintexts necessary to set up the truncated differential one. Besides that, we present new competitive low-data key-recovery attacks on 3- and 4-round AES, both in the case in which the S-Box is known and in the case in which it is secret

Plaintext Recovery Attacks against XTS Beyond Collisions

XTS is an encryption scheme for storage devices standardized by IEEE and NIST. It is based on Rogaway\u27s XEX tweakable block cipher and is known to be secure up to the collisions between the blocks, thus up to around $2^{n/2}$ blocks for $n$-bit blocks. However this only implies that the theoretical indistinguishability notion is broken with $O(2^{n/2})$ queries and does not tell the practical risk against the plaintext recovery if XTS is targeted. We show several plaintext recovery attacks against XTS beyond collisions, and evaluate their practical impacts

Practical Attacks on Reduced-Round AES

In this paper we investigate the security of 5-round AES against two different attacks in an adaptive setting. We present a practical key-recovery attack on 5-round AES with a secret s-box that requires $2^{32}$ adaptively chosen ciphertexts, which is as far as we know a new record. In addition, we present a new and practical key-independent distinguisher for 5-round AES which requires $2^{27.2}$ adaptively chosen ciphertexts. While the data complexity of this distinguisher is in the same range as the current best 5-round distinguisher, it exploits new structural properties of 5-round AES

DLCT: A New Tool for Differential-Linear Cryptanalysis

Differential cryptanalysis and linear cryptanalysis are the two best-known techniques for cryptanalysis of block ciphers. In 1994, Langford and Hellman introduced the differential-linear (DL) attack based on dividing the attacked cipher $E$ into two subciphers $E_0$ and $E_1$ and combining a differential characteristic for $E_0$ with a linear approximation for $E_1$ into an attack on the entire cipher $E$. The DL technique was used to mount the best known attacks against numerous ciphers, including the AES finalist Serpent, ICEPOLE, COCONUT98, Chaskey, CTC2, and 8-round DES. Several papers aimed at formalizing the DL attack, and formulating assumptions under which its complexity can be estimated accurately. These culminated in a recent work of Blondeau, Leander, and Nyberg (Journal of Cryptology, 2017) which obtained an accurate expression under the sole assumption that the two subciphers $E_0$ and $E_1$ are independent. In this paper we show that in many cases, dependency between the two subcipher s significantly affects the complexity of the DL attack, and in particular, can be exploited by the adversary to make the attack more efficient. We present the Differential-Linear Connectivity Table (DLCT) which allows us to take into account the dependency between the two subciphers, and to choose the differential characteristic in $E_0$ and the linear approximation in $E_1$ in a way that takes advantage of this dependency. We then show that the DLCT can be constructed efficiently using the Fast Fourier Transform. Finally, we demonstrate the strength of the DLCT by using it to improve differential-linear attacks on ICEPOLE and on 8-round DES, and to explain published experimental results on Serpent and on the CAESAR finalist Ascon which did not comply with the standard differential-linear framework